Phosphor LEDPhosphor LED.doc

Phosphor-converted light-emitting diodes (LEDs) technique is an important kind of solid-state illumination [1–4].In comparison with conventional incandescent and fluorescent lamps, the whi te LED s show many advantages such as high luminescent efficiency, long lifetime, compactness, environment friendly, and designable features. Generally, the white LEDs are realized by a co mbination of a GaN-based blue-LED chip (emitting blue light at 465 nm) with a yellow phosphor (i.e. YAG:Ce3+ -based materials). solid-state lighting based on GaN semi-conductors has attracted great attention due to its long lifetime, high luminescence efficiency, low power consumption, and environment friendliness. The most effective way to produce white light in solid-state lighting is by coating suitable phosphors on blue light-emitting diode
LED  chips. Among them, Pr3+-activated BaMoO4 deep-red-emitting phosphor has received much more attention, because it can be excited by blue light and provides remarkable deep-red emission, resulting in potential application in pc-white-LEDs based on the InGaN chip. long lifetime, high luminous efficiency, low power consumption, and environment friendliness. The most effective way to produce white light in solid-state lighting is to coat yellow light-emitting phosphors on blue light-emitting diode (LED) chips. White light-emitting diodes (LEDs) as illumination light sources have attracted more and more attention because they have advantages of precise wavelength, color output, long lifetime, reliability, energy savings, and small packaging. For a variety of applications like UV-lasers, scintillators, and lamp phosphors, the high energetic interconfigurational (4 f2?4 f 5 d ) and intraconfigurational ( 4 f2?4 f2) transitions of the Pr3+-ion are of increasing interest. Such multiphoton processes are called ‘photon cascade emission’ (PCE), ‘quantum cutting’ or ‘down-conversion’. The Pr3+-ion is in principle a suitable ion for obtaining PCE, because of